Is Scrib Nibblers legal in Standard, Modern, and Commander?

Scrib Nibblers is legal in: Modern, Legacy, Vintage, Commander.

Scrib Nibblers

Q: What type of card is Scrib Nibblers?

Scrib Nibblers is a Creature — Rat. Its oracle text reads: "{T}: Exile the top card of target player's library. If it's a land card, you gain 1 life. Landfall — Whenever a land you control enters, you may untap this creature. Power/Toughness: 1/1"